偶联剂改性氧化铈提高硅凝胶的耐热氧性能

Improvement of thermal oxygen aging resistance of silicon gel by adding modified cerium oxide with coupling agent

针对硅凝胶在使用过程中发生的变硬变脆等老化问题,本文以乙烯基硅油为基胶,含氢硅油为交联剂,氧化铝为填料制备了相应的硅凝胶弹性体。通过热重分析和马弗炉等温失重确定了硅凝胶基胶的热氧老化方式和氧化铈的抗热氧老化性能,并用三种不同类型的偶联剂对氧化铈进行了表面改性,探究了偶联剂改性氧化铈对硅凝胶耐热氧老化性能的影响。结果表明,添加偶联剂改性氧化铈可以明显提高硅凝胶的耐热性能,250℃老化8天,添加1%(质量分数)纳米氧化铈硅凝胶的拉伸强度与老化前相比增加了7.8倍,与此同时,添加1%(质量分数)KH560、6121和7707型偶联剂改性氧化铈的硅凝胶拉伸强度分别增加了2.5倍、4倍和4.7倍。综上,在老化前期,添加KH560偶联剂改性氧化铈的硅凝胶力学性能变化最小,抗热氧老化性能最佳。

For the aging problem of silicon gel hardening and brittleness in the process used,the silicon gel elastomer was prepared by using vinyl silicone oil as the base adhesive,hydrogen silicone oil as the crosslinking agent and alumina as the filler.By thermo-gravimetric analysis and isothermal weight loss in muffle furnace,the thermal oxygen aging mode of silicon gel and the antithermal oxygen aging property of cerium oxide were determined.The surface modification of cerium oxide with three different types of coupling agents was carried out,and the influence of coupling agent modified cerium oxide on the thermal oxygen aging property of silicon gel was investigated.The results showed that adding cerium oxide modified coupling agent can significantly improve the heat performance of silica gel.After aging at 250℃for 8 days,the tensile strength of silicon gel with 1%(mass fraction)nano cerium oxide increased by 7.8 times compared with that before aging.Meanwhile,the tensile strength of silicon gel adding 1%(mass fraction)of cerium oxide modified with KH560,6121 and 7707 of coupling agent enhanced by 2.5 times,4 times and 4.7 times,respectively.In the early aging stage,the mechanical properties of silicon gel adding cerium oxide modified with KH560 coupling agent had the least change with the best thermal oxygen aging resistance.